On 21 February 1943 Jacob Mossel sent the De Wit family a telegram from the Hollandsche Schouwburg requesting that they send luggage. On 4 May 1943 Jacob Mossel wrote Mrs. De Wit a letter from Vught concentration camp. The telegram and the letter remain.
Jewish Historical Museum, Documents collection, inv.nr 7313, 7317
According to a list with shops of Jewish owners, compiled by the Amsterdam police in 1940, Jacob Mossel had a bookshop, address: Oudemanhuispoort 13 in Amsterdam.
Abstracts of the police archives which are currently at the Amsterdam municipal archives